Originally Posted by phunk

I agree that there are several contributing factors to having an issue there. I'll state that my fuel systems that include rails all use -8 plumbing up to a Y split to twin -6. The rails bores are smaller than I desire for adequate fitment in a type space. We aren't going to see -8 rails fitting under a stock intake manifold so while I won't argue that it could be an alternate fix, it's not an option for the typical VQ. (BTW I know of a 370 with custom manifold and -8 rails and it's suffering rail resonance hesitations). My kits on the DE all used -6 Aeromotive regulators which I find appropriately sized for the general walbro 255 that the majority of customers use. I personally tried different fuel pressures in my 350z to no remedy. Having to make new rails was the last thing I wanted to do as i had concerns of being overwhelmed with people asking for replacements.

I'd go out on a limb and say that I doubt most race cars have them because they don't spend much time at those RPM/load sites where it causes hesitation. It is my opinion that there are probably many people suffering of the resonance and completely unaware as they probably credit it to tuning or other issue.